Well, dunno about designs but I found the actual rules for Robo-One posted here. They're called unofficial because they were independently translated from the official japanese rules. That site also has some info on various custom RO 'bots.

From the English translation of the Japanese web page, it looks like the deadline to register for the 2007 Robo-One event is Jan 20. The event will be held on Jan 27 and 28 - and some of the times of various events were still in a state of flux as of Dec 21. It doesn't appear that they have set a date for the 2008 event yet - but I would guess that it's very likely to take place early next year.